EXCERPTS: Before he died, Einstein said "Now Besso [an old friend] has departed from this strange world a little ahead of me. That means nothing. People like us ... know that the distinction between past, present and future is only a stubbornly persistent illusion." In fact, it was Einstein's theory of relativity that showed that space and time are indeed relative to the observer. Quantum theory ended the classical view that particles exist if we don't perceive them. But if the world is observer-created, we shouldn't be surprised that it's destroyed with each of us. Nor should we be surprised that space and time vanish, and with them all Newtonian conceptions of order and prediction.

When I was young, I stayed at my neighbor's house. They had a grandfather clock. Between the tick and the tock of the pendulum, I lay awake thinking about the perverse nature of time. Mr. O'Donnell is gone now. His wife Barbara, now in her nineties, greets me with her cane when I go back to visit.

We watch our loved ones age and die, and we assume that an external entity called time is responsible for the crime. But experiments increasingly cast doubt on the existence of time as we know it. In fact, the reality of time has long been questioned by philosophers and physicists. When we speak of time, we're usually referring to change. But change isn't the same thing as time.